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KRT Introduction  Taxonomy is the science of classifying and identifying plants.  Scientific names are necessary because the same common name is used for different plants in different areas of the world.  Latin is the language used for scientific classification.

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KRT Karl von Linne ( )  Swedish botanist  Developed binomial classification scheme for plants.  Uses two Latin words to indicate the genus and the species.  Changed his name to the Latin name of Carolus Linnaeus.

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KRT Scientific Names  The first word is the genus and the second word is the species.  If there are additional words, they indicate the variety or cultivar.

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KRT Archaea thrive in extreme environments  Can survive in very salty places. Salt water 3%, thrive at 15-20%  Live in water above 100 degrees C  Live in acid pools  Live in anaerobic environments

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KRT Structural adaptations  Bacteria and archaea have flagella to move about  Pili help stick to surfaces  Bacteria can form an endospore to survive harsh conditions (anthrax and botulism)  Filaments on actinomycetes allow organism to bridge dry gaps between soil particles

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KRT Bacteria  Bacteria have been on the Earth for millions of years. It wasn't until the late 1600s that scientists discovered bacteria. In fact, bacteria were discovered by accident.

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KRT  Anton van Leeuwenhoek accidentally noticed them while looking at scrapings from his teeth through a very simple microscope. He did not know what they were, but he was essentially the first person to see bacteria.

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KRT Bacteria are very small – smaller than most animal cells They can be rod shaped, spherical or spiral

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KRT Prokaryotes help recycle chemicals and clean up the environment  Cyanobacteria can convert nitrogen gas to nitrogen compounds plants can use  Live on the roots of legumes and contribute nitrogen to the soil  Breakdown of organic wastes and dead organisms to chemicals other organisms can use  Decompose organic matter in sewage sludge to material that can be used as landfill or fertilizer  “oil-eating” bacteria  Accumulate metals from mine waters

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KRT All life on earth depends on plants. Without plants ecosystems would soon grind to a halt. Animals (and fungi) are parasitic on plants.

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KRT Basics Plants (like animals and fungi) are eukaryotes. Plants are primitively photosynthetic, relying on organelles called chloroplasts to capture light energy. (A few plants have lost this ability and are parasitic on other plants). Most have highly structured bodies, with green material growing upwards and roots growing down. Their cell walls are reinforced with tough polymers, notably cellulose and lignin. All are capable of sexual reproduction, and their classification is heavily based on studies of their reproductive organs. All exhibit a phenomenon called alternation of generations, which you may well be unaware of and which we will look at closely later in the lecture.

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KRT Taxonomy - definitions Plants are widely taken to be the green things that make flowers Kingdom Plantae – algae, mosses, ferns, conifers, flowering plants In fact the boundaries are rather unclear, especially at the single-celled level. Modern taxonomies do no try to shoehorn unicellular eukaryotes into kingdoms alongside multicellular forms but prefer to handle them as a distinct group (with 27 phyla at the last count). Within plants, the term ‘alga’ is not a monophyletic group, with red alga very different to brown and green classes.

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KRT Algae  Algae are a type of protist that usually live in water and can produce their own food.

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KRT Some algae can be large, others are microscopic

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KRT Characteristics  Range in size from microscopic to single celled organisms to large seaweed  Autotrophic  Form the reproductive structures – gametangia or gamete chambers  Aquatic and have flagella at some point in life  Often contain pyrenoids, organelles that synthesis and store starch

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KRT Reproduction in Multicellular Algae  Oedogonium reproduction –Antheridium-release flagellated sperm that swim to the oogonium –Oogonium-houses the zygote which is a diploid spore  The spore undergoes meiosis and produces 4 haploid zoospores. One of the four cells becomes a rootlike holdfast the others divide and become a new filament. oogonium

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KRT holdfast

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KRT Spirogyra reproduce sexually by conjugation

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KRT Ulva Reproduces by Alternation of Generations  Two distinct multicellular phases- one is haploid and the other is diploid –Gametophyte is haploid –Sporophyte is diploid

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KRT Phylum Euglenophyta  1000 species of Euglenoids  Have both plantlike and animal-like characteristics  Fresh water

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KRT Phylum Chlorophyta  Green algae  7000 diverse species  Biologist reason that green algae give rise to land plants.  Both green algae and land plants have chlorophyll a and B as well as carotenoids and store food as starch  Both have walls made of cellulose

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KRT Phylum Phaeophyta Phylum Phaeophyta  1500 species of Brown algae  Mostly marine and include seaweed and kelp  All are multicellular and large (often reaching lengths of 147 feet)  Individual alga may grow to a length of 100m with a holdfast, stipe and blade  Used in cosmetics and most ice creams

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KRT Phylum Rhodophyta  4000 species of RED Algae  Most are marine  Smaller than brown algae and are often found at a depth of 200 meters.  Contain chlorophyll a and C as well as phycobilins which are important in absorbing light that can penetrate deep into the water  Have cells coated in carageenan which is used in cosmetics, gelatin capsules and some cheeses

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KRT Cellular slime molds  Have both unicellular and multicellular life stages

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KRT Plasmodial Slime Molds

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KRT Plasmodial slime molds  Common everywhere there is moist and decaying matter  Large and branching, but not multicellular. The weblike form increases the surface area to contact food water and oxygen  When food is is scarce it addapts the reproductive structures at the bottom

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KRT Water Molds

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KRT THERE’S FUNGUS AMONG US THERE’S FUNGUS AMONG US  Look into the eye.  Look deep into the eye.  There are no such things as molds. –All molds are actually fungi.

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KRT That's a bunch of fungus.  That is a bit surprising. We had always heard about mold in the shower or mold on the bread.

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KRT Mold is actually a type of fungus.  It has a shape called a zygote to be exact. While yeasts are single celled fungi, molds are multicellular fungi  Bread takes one kind of fungus (yeast) to make it rise.  If you leave the bread out, another type of fungus comes in (bread mold) to break it down. It's not amazing, but it's true.

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KRT Let's look at Club Fungi Mushrooms!

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KRT So what is a mushroom exactly? It is bunches of strands living underground called hyphae (pronounced hi-fah). Those strands are the basic fungus in action, decomposing leaves, or rotting bark on the ground.

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KRT When it's time to reproduce, they develop a stalk and cap,the mushroom that you see popping out of the ground.

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KRT  It's only one part of the fungus. On the bottom of that cap are a set of gills that have little clubs with fungus spores.

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KRT ZYGOTES We already talked a little about mold. That is only one example of the Zygote Fungi. These have hyphae-like mushrooms but they reproduce in a different way. When it's time to make more fungi, they create a stalk and release something called zygospores (thus the name zygote). These have hyphae-like mushrooms but they reproduce in a different way. When it's time to make more fungi, they create a stalk and release something called zygospores (thus the name zygote).

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KRT  When your bread gets old and green or black, you are seeing a type of zygote fungus in action. If you wait long enough, you will see the stalks develop and the zygotes released.

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KRT Fungi  Heterotrophic – they cannot make their own food molecules  Some like mycorrhizae absorb essential minerals from the soil needed by plants  About 80% of plant disease is caused by fungi which are parasites  Many decompose organic matter

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KRT Fungi absorb food after digesting it outside their bodies  Secrete powerful enzymes that digest their food externally then absorb the nutrient molecules  Multicellular except yeast  Mycelium is a feeding network of hyphae  Mushroom is just the above ground reproductive structure of a much more extensive underground mycelium  Not celllulose cell walls, but chitin which is a polymer of a nitrogen- containing sugar  No flagellated cells in their life cycle

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KRT Lichens – fungi living mutualistically with photosynthetic organisms  The mutualistic merger is so complete they are actually named as a species  Gives the two organisms the ability to survive in habitats that are inhospitable to either alone  Can tolerate severe cold, withstand severe drought but sensitive to air pollutants

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KRT , I am not mold ! I am not rotting you! I am Mycorrhizae, I am a fun guy

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KRT Fungi have enormous ecological impact  Decomposers and recyclers of organic matter  Used to ripen cheese  Yeasts used in baking, brewing and winemaking  Produce antibiotics  As well as the mutualistic partners in mycorrhizae and lichens

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KRT YEAST YEAST Yeast is used to make several types of food for humans. We need yeast to make breads. We also use them to make alcohol. It's a whole process called fermentation.

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KRT Some fungi are beneficial.  Sugars are broken down in an environment without oxygen. It's called anaerobic fermentation. And voila, alcohol. Even though they are single celled, you may find them in colonies. They reproduce very quickly and hang out together. It takes a lot of them (because they are so small) to get a lot of work done

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KRT Bryophytes  Includes mosses  Have a cuticle and embryos retained on the parent plant  Lack vascular tissue, but some have water- conducting tubes  Lack internal support  Plants grow in a tight pack holding each other up  Flagellated sperm must swim

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KRT Bryophytes These are the mosses and liverworts, both relatively common well- known groups of non-flowering plants typical of permanently damp areas. (Actually a few specialise in dry open sites – fire sites, bare concrete etc). The dominant phase is a leafy form (the gametophyte), which is genetically different to the stalked pods that produce its spores. A typical moss, showing the spore capsule, which is a genetically different plant to the green fronds from which it grows. (More later..)

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KRT The hepatica: Liverworts. These also make genetically distinct spore-dispersing individuals, but here the spores are dispersed from an umbrella-like structure, while the main plant (the gametophyte) is generally flattened, plate-like. The common liverwort Marchantia sporophytes c. 2 cm

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KRT Seedless vascular plants  Includes ferns  Well-developed roots and rigid stems  Flagellated sperm that require water to reach eggs  In many species the leaves sprout from stems that grow along the ground (fiddleheads)

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KRT Pteridophytes: ferns, horsetails, club mosses and allies. Pteridophytes are the group of plants which first (as far as we can tell…) developed the tracheid cells which permit stems to rise high above any water supply, and as such were the first colonists of dry land, at least 400 MYBP. We have a good fossil record of them (in fact our industry has depended on burning this fossil record since the inception of the industrial revolution!). The facets which fossilise show that apart from the extinction of the giant forms, this group has changed little since the Devonian. Like mosses these plants have two genetically distinct phases in their life cycle, but here the dominant phase is the sporophyte, the familiar fern leaves etc.

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KRT Ferns These are ancient but still successful forms, in which the spore-bearing stage is very familiar. Bracken Pteridium aquilinum is one of the most widespread and pernicious weeds on the planet! We still have tree ferns, native to Gondwanaland (Australasia, South America, Africa) but now widely planted in tropical, subtropical and frost-free temperate areas. In all cases spores are shed from the underside of the leaves (fronds). Bracken Pteridium aquilinum A tree fern Dicksonia antarctica

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KRT Horsetails (Sphenophyta): Equisetacea These plants are every-day miracles. There are only about 15 species in the world, all in the genus Equisetum. It has changed hardly at all since the carboniferous period. I know of a Carboniferous site in Yorkshire where one can find 2m high horsetails still standing, fossilised in a cliff, looking exactly like living forms (only rather bigger, though giant horsetail E. telmateia can grow nearly this tall). Also known as Lego plants, because the stems comes apart at the nodes.

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KRT The needle-like leaves are reinforced with silica, and have been used as pan scrubs. Few animals find them palatable. For all their ancientness and oddity they are a serious weed, with immensely deep root systems and an ability to shrug off herbicides. Gardeners’ Question Time (BBC) advice on how to respond to horsetails in your garden Sell your house, in winter when the stems aren’t visible. Horsetails, contd.

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KRT Club mosses (Lycophyta): Lycopodiacea These rather nondescript crawling plants are nowadays confined to a minor role in northern forests on acid soils. Present in the UK but easily overlooked. The sole survivors of a large group including vast forest- forming trees in the carboniferous, the first terrestrial forests. The have a vascular system, and always one vein running along the leaf axis.

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KRT Gymnosperms  Naked seed because it isn’t produced in a specialized chamber  Conifers – pine, spruce, and fir are the largest group

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KRT Gymnosperms This group contains many well-known plants, including all coniferous trees (pines, larch, spruce etc), yews and allies, along with other ‘living fossils’ the cycads, plus a few simple plain oddities thrown in to keep botanists happy. Gymnosperm means ‘naked seed’, and indeed in this group the fertilised seed protrudes from the cone/aril. They have apparently lost the sporophyte generation (but see later), and are now trees which shed viable seed that germinates to make a new tree – the pattern of seed germination which we are familiar with. They have tracheids allowing water to be sucked to great heights: the this group contains probably the largest (Sequoia) and oldest (Bristlecone pine, Pinus aristata) organisms in the world.

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KRT Cycads  Most diverse during age of dinosaurs  Only 100 living species  Palmlike appearance  Pollen-bearing and seed-bearing cones on different plants Do not post on Internet Figure 23.14e Page 394 Strobilus of a “female” cycad

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KRT Cycads These plants look rather like stunted palms, or possibly rather tough tree ferns, but are neither. They are gymnosperms that have changed little since the Jurassic period, when they were dominant land cover and presumably staple food for herbivorous dinosaurs. Now they are thinly scattered in tropical areas, some highly endangered. Males and females plants are separate, using a wind- dispersed pollen to fertilise their cones. The male gamete is notable for using cilia to swim towards the egg (the ‘highest’ occurrence of cilia in the plant kingdom). Some cycads fix atmospheric nitrogen using a symbiosis with blue-green algae living in their stems and roots.

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KRT Ginkgo biloba – the wonderful discovery People had since the early days of fossil hunting been recovering well-preserved fossil leaves from Ancient (Jurassic and earlier) which looked like an unrolled pine needle. No living plant matched this pattern. Then in 1691 the German Engelbert Kaempfer discovered strange trees with exactly this unfamiliar leaf form in Japan, cultivated in temple gardens. They proved to be living specimens of Ginkgo, one male and one female. Thankfully their seed was fertile, and has now been widely propagated. The oldest in the UK is in Oxford botanic gardens (pruned and now rather small for its age). Generally males are planted as the female flower is rather sticky and smelly. (Sex is coded by an X-Y chromosome system, as in mammals).

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KRT Welwitschia mirabilis This is certainly one of the strangest plants in the world, whose classification inside the gymnosperms has long been assumed but is confirmed by DNA analyses. It lives only in the Namib desert, South Africa, in a region where rain never falls. Instead it relies on the mist that condenses in coastal regions where cold currents from the southern oceans well up against the desert. Welwitschia has only 2 leaves, long strap-like ones that grow perpetually from their base while the ends become frayed and tatty. It is dioecious.

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KRT Pine Cones Pine Cones  Woody scales of a “pine cone” are the parts where megaspores formed and developed into female gametophytes  Male cones, where microspores and pollen are produced, are not woody

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KRT Conifer Distribution  Reproduce more slowly than angiosperms; at competitive disadvantage in many habitats  Still dominate in far north, at higher elevations, and in certain parts of southern hemisphere

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KRT Angiosperms: Monocotyledons and Dicotyledons Flowering plants (phylum Anthophyta) come in two fundamentally different ‘designs’ or classes, known as the Monocotyledons and Dicotyledons. Or Monocots and Dicots in botanical jargon. Formally these are defined by the number of seed leaves, or cotyledons, that emerge when the seed 1 st germinates. In Monocotyledons it is 1, in Dicotyledons it is 2. Coinciding with this are a series of other characteristics which are so consistent that everyone seemed happy that these are monophyletic groups, splitting from the gymnosperms about 130 MYBP (early Cretaceous).

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KRT Monocotyledons This truly monophyletic group contains all grasses, sedges, rushes, bamboo etc. Orchids. Pineapples and allies (the bromeliads). Lilies, and their succulent relatives Aloes. Few trees but including bananas and palms.

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KRT Dicotyledons. Actually the eudicotyledons plus a few others… It is here that I have to confess to a certain oversimplification. Neat though the division was, recent (late 1990s) DNA work has shown that the group known as ‘Dicots’ consists of 4 groups, all as unrelated to each other as they are to the monocots. Fortunately, virtually all the ones you are likely to meet are in a good monophyletic group, now called the Eudicotyledons. (Sometimes DNA research makes a good simple system needlessly complicated..)

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KRT Eudicotyledons Here we have most gardens flowers, all herbs, cacti, climbers, and most trees.

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KRT People and Plants People and Plants  Plant domestication began about 11,000 years ago  About 3,000 species have been used as food  Now about 200 plants are major crops

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KRT Plants of Abuse  Tobacco plants are Nicotiana sp.  Cannabis sativa is source of marijuana  Coca leaves are used to produce cocaine  Toxic plant alkaloids, such as henbane and belladona, have been used as poisons and as medicine